Involving stakeholders in the evaluation of management strategies for shortfin mako (Isurus oxyrinchus) and blue shark (Prionace glauca) in the Spanish longline fisheries operating in the Atlantic Ocean

摘要

Shortfin mako (Isurus oxyrinchus) and blue shark (Prionace glauca) are a relevant bycatch in the Spanish surface longline fisheries that operate in the Atlantic Ocean. Concern has been raised after the 2017 and 2019 shortfin mako evaluations for the Northern Atlantic stock. It stated the population being overfished and suffering from overfishing. Also blue shark is subject to high extraction rates in the Atlantic Ocean. Few data and uncertainty in assessment results suggest that further management strategies could be taken into account for both species. This study evaluated different fisheries management strategies for shortfin mako and blue shark in the Atlantic Ocean from the stakeholders' perspective. Personal interviews were conducted with Spanish fishermen and surveys were sent to scientists and non-governmental organizations (NGOs). Local Ecological Knowledge was considered to be useful as fishermen possess unique expertise based on their continued interaction with the species and environment. Interviews allowed understanding the fishermen's perception on variations of stock abundance, distribution patterns, size of capture and seasonal fluctuations for both species. SWOT (Strength, Weaknesses, Opportunities and Threats)-analysis was used to study the different management measures. Main management strategies proposed by all stakeholders to reduce the bycatch of both species were spatial-temporal closure, minimum size and quotas. The Sole Bank was suggested as a temporarily closed area to protect blue shark juveniles during the summer months. The participation of stakeholders enriched the knowledge available and provided a broader data set now available for decision makers in the corresponding regional fisheries management organization (RFMOs).